33984 A rare genodermatosis with an unusual presentation: A case of Galli-Galli

Abstract

Introduction: Galli-Galli disease (GGD), a rare acantholytic variant of Dowling-Degos disease (DDD), is a genodermatosis characterized by progressive, reticulate, pigmented lesions of intertriginous and flexural sites. We present a unique case of GGD that spared the intertriginous areas and histologically mimicked seborrheic keratosis. Results: A 53-year-old female with a history of mild hidradenitis suppurativa (HS) presented with a pruritic rash of greater than 5-year duration. Physical examination was notable for innumerable well-defined, reticulated, erythematous to light brown papules and macules on the bilateral upper and lower extremities. The patient’s father and sister had similar lesions. Previous biopsies showed features of seborrheic keratosis or Grover disease. Repeat biopsy demonstrated slight papillated epidermal hyperplasia with elongation of rete ridges. A focus of acantholysis in the epidermis was noted in deeper sections. Histopathologic and clinical features could represent Galli-Galli disease. Treatment with triamcinolone 0.1% ointment did not alleviate the pruritus; the patient was started on a trial of halobetasol 0.01 %/tazarotene 0.045%. Conclusion: GGD is inherited in an autosomal dominant fashion with a mutation in the KRT5 gene, resulting in disruption of basal keratinocyte integrity. A subset of GGD cases has been reported in non-classical sites and does not carry the KRT5 mutation; the distribution of this case fits this unusual subset. Rarely, as with the current case, GGD is associated with HS along with mutations in the gamma-secretase complex and POFUT1 genes. This case highlights a nonclassical case of GGD, its rare association with HS, and salient clinical and histologic diagnostic features.